Mayan apocalypse: 100 places to see before the end of the world - part one

This complex of Eastern Orthodox monasteries near Kalambaka, Greece, is a
testament to faith, ambition and engineering. The six buildings are built
atop natural sandstone pillars, some of which stand 550 metres high. Erected
between the 14th and 16th centuries, access was initially via long, rickety
ladders, which were only replaced "when the Lord let them break". Steps were
later cut into the rock.

Cheaper alternative?

Mussenden Temple, on the cliffs near Castlerock, in County Londonderry.